24V to 12V Converter - Lifespan?

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Texas710
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24V to 12V Converter - Lifespan?

Post by Texas710 » Wed Oct 21, 2015 8:44 pm

I have a 24V to 12V converter and it's been acting up.

Sometimes when I start/run the truck, my 12v system is not working. I know this because it runs my RPM gauge and some accessories in the cab. This does not happen all the time and will usually resolve itself if I pull out the blade fuse (of the converter) and put it back in. Not that the fuse is blown, just what I have found helps bring the thing back online, may just be coincidence.

Do these things have a lifespan? Not sure on the age as it came with the truck. Maybe there is something loose in there that gets better when re-adjusting the fuse? If this one goes, anybody have another they like?

This is the type I have.
Sanel SC2420. 24V - 12V/20A DC/DC Converter

Thanks

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Jimm391730
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Re: 24V to 12V Converter - Lifespan?

Post by Jimm391730 » Wed Oct 21, 2015 10:23 pm

My first converter was a Samlex, and it only lasted a year before it started acting up in cold weather (not working) and eventually wouldn't work even in warm weather. It is just the quality of the design and quality of construction.

However, since then I've had three MeanWell converters (sold and badged as Astrodyne - at least I'm pretty sure they are MeanWell parts) and all three are still working fine after many years. I know that Jim L. has also been buying the parts from Astrodyne and I believe he has also had good results. The largest one that I have is rated at 350 watts (almost 30A) and has been running my EFI system, ignition and fuel pump for over six years now. This higher wattage unit does have a fan, but even that is going strong (fans are one of the most unreliable parts). Best of all, the Astrodyne parts are not too badly priced and you can order them in single units.

The larger unit I have is their SD350B-12 (http://ecatalog.astrodynetdi.com/usa/en ... /SD350B-12) but be careful - I just noticed that their website has some errors. The SD350 is the basic model and power level (350W), the "B" means 19-36 volts input, and the "-12" is the output voltage. So always be certain to get a unit that ends in "B-12" for our applications.
Jim M.
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rmel
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Re: 24V to 12V Converter - Lifespan?

Post by rmel » Thu Oct 22, 2015 12:30 am

Well there's a little bit of a clue here. Toggling the fuse out and back in gets the converter going.

That's essentially a power reset of the unit -- however, your engine is running and likely the input
to the converter is at ~26V. When you have the problem you are cranking your engine and thus
less than 24V.

It's possible that a internal component of the unit may have degraded resulting in the converters
internal controller getting in a bad state during cranking, e.g. hung, and essentially won't "boot" so
to speak. Or this is just a weakness of this particular converter design which could get exposed
when the input voltage is below a certain minimum value e.g. when your cranking and you got weak
batteries too.

You might want to measure your voltage when cranking to make sure it's not time for new batteries
and your cnverter was just the canary. If not, then it's time for a new converter. As Jim pointed out
Meanwell, and Samplex are decent, my leaning is toward Victron Orion series, more industrial strength
along with your wallet.

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Re: 24V to 12V Converter - Lifespan?

Post by krick3tt » Thu Oct 22, 2015 7:46 am

I am guessing that like many electronic devices that have issues, they may fall prey to the bumps and jolts of off road driving. I had to replace a CB unit that had a problem with loose solder joints that were not diagnosed until after it was replaced. Cost more to fix it than it was worth.
I got one that is intended for heavy hauler semi trucks that are meant to be bounced around. Been fine since replaced.
Have not had issues with my converters as yet.

Wrong pic...ignore this ...can''t delete it
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Re: 24V to 12V Converter - Lifespan?

Post by ako » Thu Oct 22, 2015 9:46 am

krick3tt wrote:Wrong pic...ignore this ...can''t delete it
Off topic, but what is in the centre area of your truck bed? A slide out drawer or tanks? Access hatches?

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Re: 24V to 12V Converter - Lifespan?

Post by krick3tt » Thu Oct 22, 2015 10:23 am

PM sent
Any man who thinks he can be happy and prosperous by letting the government take care of him:
better take a closer look at the American Indian.---Henry Ford

Texas710
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Re: 24V to 12V Converter - Lifespan?

Post by Texas710 » Thu Oct 22, 2015 1:17 pm

No worries about the picture, I have always liked the back of your rig, the rug really pulls it together!

Rmel, you might be onto something. The truck is off site while I try to sell my house and while I was cracking it to start, I noticed both batteries were getting down into the 10 volt area (I have dual digital battery monitors). I think it may be time for an independant battery charge. I do drive it, but not as often as I probably should with everything going on.

I have had this issue before this as well, so I will be doing some homework on the suggested units.

You guys are such a wealth of information. Thanks again for everything.

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rmel
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Re: 24V to 12V Converter - Lifespan?

Post by rmel » Thu Oct 22, 2015 3:52 pm

By the way, deepening upon the 12V devices you are powering, if you
are going to replace your converter there is also the option of using a
Battery Equalizer, Vanner is the defaco king in this area esp. with the
Maritime boys so very reliable. What this device will do is essentially
provide a virtual 12V battery output to run all your 12V gear -- it will
provide EQUAL charge out of both batteries so they wear identically.
These units are extremely efficient ~97% and can provide 30A or more
in a very compact size that can fit in your battery box. The disadvantage
is that it's going to act like a battery as the pair discharge your 12V will
drop accordingly. This may not matter for what your running, but it would
matter a lot if your running HAM gear or fuel injectors that want to see a
fixed voltage at 13.3V or higher to minimize turn-on latency.

So all depends on what you got, and where your heading.

cheers,

ron
Puller: 710K 2.7L EFI
Follower: Sankey MK 3, 3/4 Tonne
Driver: Ron // KO0Q

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Re: 24V to 12V Converter - Lifespan?

Post by Texas710 » Thu Oct 22, 2015 4:20 pm

The converter in the truck now powers a Ham and CB, but I do not have my Ham operating licence, so I don't use that as of now. I will want to keep the same set up because I am sure I'll need all that gear someday, or at least the next owner of my truck might. So many options, I am going to be doing a lot of research this weekend.

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Re: 24V to 12V Converter - Lifespan?

Post by TechMOGogy » Thu Oct 22, 2015 7:30 pm

rmel wrote:By the way, deepening upon the 12V devices you are powering, if you
are going to replace your converter there is also the option of using a
Battery Equalizer, Vanner is the defaco king in this area esp. with the
Maritime boys so very reliable. What this device will do is essentially
provide a virtual 12V battery output to run all your 12V gear -- it will
provide EQUAL charge out of both batteries so they wear identically.
These units are extremely efficient ~97% and can provide 30A or more
in a very compact size that can fit in your battery box. The disadvantage
is that it's going to act like a battery as the pair discharge your 12V will
drop accordingly. This may not matter for what your running, but it would
matter a lot if your running HAM gear or fuel injectors that want to see a
fixed voltage at 13.3V or higher to minimize turn-on latency.

So all depends on what you got, and where your heading.

cheers,

ron
Not to go to far off topic but I guess you could run a small 12 v battery and then add a 24v to 12v charger
Thoughts on that kind of setup?
72 Pathfinder | 75 710M 2.7i | 94 350GDT | 96 350GDT Worker

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Re: 24V to 12V Converter - Lifespan?

Post by rmel » Fri Oct 23, 2015 10:08 am

Yes, that's an alternative. 12V Battery charged by a 24V-12V battery charger.

With that approach the only real advance would be isolation from the 24V system
when not running -- thus not draining your starting batteries. To do that you would
need a charger you can control ON/OFF via ign. switch. You would also still need
to size the convert to the load; same output capacity as a Converter or an Equalizer.

The real advantage of a separate 12V battery comes to play when charged via Solar
(and the 24V alternator). REDARC (Aus) has a charger that can take as input direct
Solar panels OR 24V Alternator OR 12V Alternator AND charge a 12V battery. This
is how I am set up with 4 12V Yellow Tops + 2 Siemens Panels. These chargers
are very pricey but extremely reliable, you have to do the import yourself. I have way
too much electronics stuff in my truck that I run off-grid, most don't need this.

ron

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Re: 24V to 12V Converter - Lifespan?

Post by krick3tt » Fri Oct 23, 2015 10:21 am

I run an alternate 12V battery and charge it (through a solar regulator (https://www.altestore.com/store/Charge- ... n3/p10508/) off a flexible solar panel on the roof. Used when traveling and camping mostly for the ARB cooler. The 12 to 24 converter is cut off from the vehicle system with a switch when I don't need to have the Webasto operating.
I do find that it is to my advantage to park in the sun for the panel and that makes for some relatively warm temps in the pinz.
I did have another converter for radio, GPS and CB but removed it when the splitter was installed, now it is a spare located in my shop.
Adding extra electronic items to an existing system does take some round-about thinking in order not to exceed the limits of the old existing alternator.
Last edited by krick3tt on Fri Oct 23, 2015 4:24 pm, edited 3 times in total.
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better take a closer look at the American Indian.---Henry Ford

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Re: 24V to 12V Converter - Lifespan?

Post by Texas710 » Fri Oct 23, 2015 4:03 pm

Yes, some round about thinking indeed.

I am going to have to think for the future, when I would like to install the SSI system. Also on the dream list would be a fuel pump, but I think that's at least a year out... The solar panel/charger is another piece I have been thinking about.

Jimm391730, sounds like you have a finished setup close to where I want to be. I appreciate the size and link, those look nice. Correct me if I am wrong, but doesn't the trucks ability to function depend on that converter, if the fuel and SSI are run off it? What happens if it goes while driving down the road, or off down a trail somewhere? That said, 6 years dependability is good enough for me, but a backup would be nice.

Complex stuff

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Re: 24V to 12V Converter - Lifespan?

Post by rmel » Sat Oct 24, 2015 11:24 am

If you want my $0.02 on a recommendation :D

If you are planning on SSI and later an independent 12V Battery/Solar then you should go belts and suspenders.

Anything to do with ignition or engine control should be on it's own private power source derived from the 24V battery.
That should be a 24V/12V converter not an equalizer to maintain a constant 13.3V to 13.8V output under load.
Watch out for the converter you pick minimum input voltage requirement. For example the Translectric 24/12 converter
has a 20V min and they mean it -- I measured this unit on the bench it's output goes to ZERO with an input of 19.5V.
That's not good if you happen to be cranking with somewhat discharged batteries you will not start -- yes this happened
to me. The Samplex SDC-23 converter has exactly the same input spec but on the bench operates under load down
to 16V (although I could see the unit begin to go out of regulation at that point but it would be good to start).

You could run your other toys off this converter then later if you add a separate 12V battery and Solar move the toys
over to that system and keep your converter for SSI/EFI private.

As a tip, if you can put these two systems next to each other in the case that one fails you could hot wire over to the
other as a redundant system -- yes I did just that once :D

I am now literally installing a 12V Booster on my battery system -- yup but yet another 12V alternative for off-grid
Radio from TGE Electronics, it NEVER ends, NEVER :(

ron

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Re: 24V to 12V Converter - Lifespan?

Post by Jimm391730 » Sat Oct 24, 2015 12:16 pm

doesn't the trucks ability to function depend on that converter, if the fuel and SSI are run off it? What happens if it goes while driving down the road, or off down a trail somewhere?
True, very true. The 29 amp unit is running my EFI and pump, so normal current draw is under 10 amps (but I also use the same converter for my 50W Ham radio, 10A max, due to physical placement). Since I'm comfortable with all this I have a few emergency options: the "normal" converter (150W, 12.5A version) can be moved or rewired if the 300W converter was to fail, or I could power from either of my two large 100ah "house" batteries, or power from the tap of the chassis batteries. I have a selection of wire and multimeters always in the truck so I can (hopefully!) detect and repair most electrical issues that come up.

For more reliability I could duplicate the converter, and hook them through large diodes to have redundancy in case one was to fail.
Jim M.
712W and 710M

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